Projectile hit scorers comprising target hit indicators and projectile identifiers are known. These devices are used to score a hit on a target by various types of weapons and to identify hits of projectiles of different calibers. For example, U.S. Pat. No. 3,602,510 discloses a projectile hit scorer and detector comprising a conductive layer and a non-conductive layer ahead of the conductive layer. An impacting projectile on the non-conductive layer loses its kinetic energy causing electrons to flow into and out of the conductive layer through a load circuit. It is indicated that as a projectile passes through the air it accumulates a charge. When the projectile impacts a voltage is generated. The resultant pulse amplitude and duration is indicative of the energy in the projectile and permit identification of hits by projectiles of different caliber. The measurement of energy requires both amplitude and duration to be measured requiring an oscilloscope or, in the alternative a voltmeter and counter. The measurement of energy is somewhat cumbersome. Further, the patent states that the target signal generation awaits further test verification and experimentation, indicating that the disclosed method of projectile hit scoring is subject to possible error.
U.S. Pat. No. 3,727,069 discloses a target measurement system for precise projectile location. This system uses collimated light beams in a grid network to identify target location and diameter of a penetrating projectile which intercepts the beams. This system is complex and costly. Further, if a projectile misses the target area and impacts the light sources the target could be disabled. This is not desirable in a military training application where, for example, the target may be located 3000 feet or more from the projectile firing apparatus, and subject, therefore to large impact locating errors.
Other systems are known for recording hits on targets as shown for example in U.S. Pat. Nos. 3,112,110; 3,004,763; 2,749,124; 2,749,125; 4,240,640 and 3,401,939, the latter two patents being commonly owned with the present invention and incorporated by reference herein. The mere recording of hits on a target, however, is not as desirable as identifying the type of projectile making the hit and also, identifying a given target among an array of targets.
The present inventors recognize a need for a low cost, simple apparatus for both identifying projectiles hitting a target by projectile type and also for distinguishing between targets hit. The target must also survive hits throughout the target without impairing the target's ability to function so as to withstand numerous hits from a variety of types of projectiles. The projectile types must be identified repeatedly and reliably with a high degree of accuracy. Further, the identification must be made simply so that unskilled persons can readily read the results quickly and accurately.